Week 5 Flashcards
List the 10 features of Parkinson’s Disease?
- Tremor at rest
- Rigidity: cogwheel, limbs>axial
- Bradykinesia
- Asymmetry
- Loss righting reflex
- 30% cognitive decline
- Hypomimia (lack facial expression)
- Glabellar tap
- Quiet Speech
- Micrographia
What neurotransmitters inhibit & excite the basal ganglia?
- INHIBIT: GABA
- EXCITE: Glutamate
What happens in the substantial nigra dopaminergic part of the corticospinal pathway?
- Turns up direct pathway
- Turns down the indirect pathway
- Increases VA/VL drive to cortex
- MORE MOTOR ACTIVITY
Describe the direct corticospinal pathway?
- Increases excitatory thalamic input to cortex
- TURNS UP MOTOR ACTIVITY
Describe the indirect corticospinal pathway?
- Decreases excitatory thalamic input to cortex
- TURNS DOWN MOTOR ACTIVITY
What happens in the Striatal interneuron cholingeric part of the corticospinal pathway?
- Turns down direct pathway
- Turns up indirect pathway
- Decreases VA/VL drive to cortex
- LESS MOTOR ACTIVITY
What happens to the corticospinal pathway in Parkinson’s disease?
- Substantia nigra dopamine cells lost, therefore indirect pathway increases
- Dopamine inhibition lost (disinhibition)
- ACh excitation unopposed
- LESS MOTOR ACTIVITY
What 9 factors can lead to Neurodegeneration?
- Toxins
- Protein handling disorders
- Lack of growth factors
- Oxidative stress
- Excitotoxicity
- Ionic disequilibrium
- Mitochondrial dysfunction
- Activation of cell death pathways
- Immune attack
What is the main strategy in drug treatment of Parkinson’s disease?
Counteract deficiency of dopamine in basal ganglia
What are the 5 different drug treatments for Parkinson’s disease?
- Levopoda (1st line)
- Dopamine agonists
- Monoamine oxidase B (MAO-B) inhibitors
- Amantadine
- Muscarinic ACh antagonists
What is Levodopa used in combination with to treat Parkinson’s disease?
Dopa decarboxylase inhibitor (carbidopa or benserazide)
What do 80% of patients on Levodopa for Parkinson’s show?
Initial improvement in rigidity & hypokinesia
What does L-dopa show no evidence of?
That it slows or accelerates neurodegeneration
What are the potential side effects of Levodopa?
- Involuntary writhing movements (dyskinesia) within 2 years (face & limbs mainly), at peak therapeutic effect
- Rapid fluctuations in clinical state
- Hypokinesia & rigidity may suddenly worsen & improve again
Give examples of Dopamine agonists?
- Pramipexole & Roprinole (D2/3 selective receptor agonists)
- Bromocriptine, Cabergoline & Pergolide (oral D1 & D2 receptors)
- Rotigotine
- Apomorphine
What 2 dopamine agonists are better tolerated?
- Pramipexole
2. Roprinole
What is the limiting side effect of Bromocriptine, Carbergoline & Pergolide dopamine agonists?
Fibrotic reactions
How is Rotigotine dopamine agonist administered?
Transdermal patch
How is Apomorphine dopamine agonist administered?
Injection, sometimes to control off effect of Levodopa
Describe the characteristics of Dopamine dysregulation syndrome?
- Sudden onset sleep
- Impulse control disorders (gambling, binge eating)
- Hypotension
- Neuroleptic malignant syndrome if stopped abruptly
Give 2 examples of MAO-inhibitors for Parkinson’s disease?
- Selegiline
2. Rasagiline
Describe Selegiline (MAO-inhibitor)?
Selective MAO-B which lacks unwanted peripheral effects of non- selective MAO inhibitors
What does inhibition of MAO-B do?
Protects dopamine from extraneuronal degradation
What does a combination of MAO-inhibitors & Levodopa provide?
More effective in relieving symptoms & prolonging life
Describe Rasagiline (MAO-inhibitor)?
Alternative & may retard disease progression
Describe the use of Amantadine in Parkinson’s disease?
- Antiviral drug
- Increased dopamine release
- Less effective than levodopa/bromocriptine & action declines with time
How do acetylocholine antagonists work for treatment in Parkinson’s disease?
Exert inhibitory effect on dopaminergic nerves, suppression then compensates for a lack of dopamine
Give 3 examples of Acetylcholine antagonists used in treatment for Parkinson’s disease?
- Benzhexol
- Orphenadrine
- Procyclidine
What is used in severe cases of Parkinson’s disease?
- Electrical stimulation of subthalamic or Gpi nuclei by inserted electrodes (DBS)
- Can improve motor dysfunction
What does combining Levodopa with a dopa decarboxylase inhibitor provide?
Lowers the dose needed & reduces peripheral system effects
What’s a disorder that can occur from an unstable trinucleotide repeat in the exonic coding region?
Huntington’s Disease
polyglutamine in coding region
What’s a disorder that can occur from an unstable trinucleotide repeat in the 5 prime untranslated region?
Fragile X syndrome
What is a disorder that can occur from an unstable trinucleotide repeat in the intronic region?
Fredreich’s Ataxia
What is a disorder that can occur from an unstable trinucleotide repeat in the 3 prime untranslated region?
Myotonic Dystrophy
Describe the characteristics of Huntington’s disease?
- Autosomal dominant
- Begins in midlife
- Chorea, dystonia, behavioural & psychiatric changes, gradual loss of cognition
What structures in the brain are affected in Huntington’s disease?
- Striatum most severely affected
- Atrophy of caudate nucleus & putamen
What does CAG code for?
Glutamine
Why is the insertion of extra glutamine residues in Huntingtin’s protein harmful?
- Protein misfolds
- Aggregates
- Inclusion bodies
What are the 2 ethical questions surrounding Huntington’s disease?
- Does an asymptomatic at-risk individual have a duty to undergo testing & learn result before reproducing?
- Is it ethical to allow asymptomatic children from families with HD to be tested?
Describe the characteristics of Fragile X syndrome?
- Leading cause of inherited mental impairment
- Single gene disorder on X chromosome
- Males & females all ages & ethnic groups
Where is the “fragile” site located for Fragile X syndrome?
Chromosome Xq27.3
What are the signs & symptoms of Fragile X syndrome?
- Long face (prominent forehead & jaw)
- Mitral valve prolapse
- Mental impairment
- Attention deficit / hyperactivity disorder
- Autistic-like behaviour
What protein is associated with Fragile X syndrome?
FMR1
What does the expansion of DNA in Fragile X syndrome result in?
Transcriptional silencing
What is the purpose of FMR1 protein?
Fragile X syndrome
- Highly expressed in neurons
- Regulates mRNA translation in dendrites
Describe the DNA expansion mechanism?
Triplet repeats in human disease can adopt hairpin conformations in vitro at physiological salt levels & temperatures
What is the definition of Genetic Anticipation?
Genetic disorder is passed onto next generation, symptoms become apparent earlier with each generation & increase in severity
What 3 things does genetic anticipation help with clinically?
- Diagnosis
- Genetic counselling
- Treatment
What are the 2 different types of Alzheimers disease?
- Early onset
2. Sporadic
Describe the characteristics of Early onset Alzheimer’s disease?
- Autosomal dominant
- ~5% of all Alzheimer’s
- Down’s Syndrome high risk
What is Amyloid precursor protein (APP) normally cleaved by?
Alpha-secretase & cut into smaller fragments
What happens during Amyloid precursor protein (APP) mutation?
- Increase beta-secretase cleavage of APP
- Leads to excess amyloid accumulation
- Beta-amyloid gives rise to plaques
- Synaptic loss & neuronal death leading to Alzheimer’s
What do mutations in Presenilin 1 & 2 cause?
associated with Alzheimer’s disease
Affect the activity of the gamma-secretase enzyme complex
What gene mutation is involved in sporadic Alzheimer’s disease?
Apolipoprotein E (APOE)
What are the 3 alleles for APOE gene?
e2, e3 & e4
differ by single amino acid
What risk of developing Alzheimer’s disease does heterozygotes for e4 (APOE allele) have?
3 fold risk
What risk of developing Alzheimer’s disease does homozygotes for e4 (APOE allele) have?
15 fold risk
What are the functions of the APOE gene (Apolipoprotein E)?
- Cholesterol transport
- Clears amyloid beta
What can the breakdown of APOE e4 allele cause?
Generate toxic products
What 3 other gene replications are associated with Alzheimer’s disease?
- Clusterin
- PICLAM
- CR1
Describe neurofibrillary tangles?
- Insoluble twisted fibers found inside the brain’s cells
- Consist primarily of tau protein, which stabilises microtubule
Describe neurofibrillary tangles in Alzheimer’s disease?
Tau protein is phosphorylated & the microtubule structures collapse due to depolymerisation
When would you see neurofibrillary tangles but NO plaques in Alzheimer’s disease?
Fronto-temporal dementia with Parkinsonism
How can you therapeutically target neurofibrillary tangles & amyloid plaques in Alzheimer’s?
- Secretase inhibitors
- Prevent phosphorylation of Tau
- Aggregation inhibitors (Tau & amyloid beta)
- Statins
- Immunization
What 3 different prion diseases are grouped as “Transmissible Spongiform encephalopathy”?
- Creutzfeld-Jakob Disease (CJD)
- Fatal familial insomnia
- Kuru
Describe the characteristics of Prion diseases?
- Inherited (10-15%)
- Sporadic (85%)
- Acquired (normally rare)
What are Prion diseases also known as?
Transmissible Spongiform encephalopathy
Describe a Prion?
- Proteinaceous/Infectious
- Progressive neurodegenerative
- No genetic material
- Exist in animals & humans
What is the normal & abnormal infectious Prion’s known as?
- NORMAL: PrPc
- ABNORMAL, INFECTIOUS: PrPsc
What are the 3 normal functions of the PRPN Prion?
- GPI-anchor
- Glycosylated
- Synaptic membranes of neurons
What are the 3 therapies for Prion disease?
- Stabilising PrPC conformation
- Clearance of PrPSC
- Vaccination against PrPSC
What causes an abnormal red reflex?
Anything obstructing path of light from front to back of the eye:
- Corneal Scar
- Cataract
- Vitreous Haemorrhage
- Retinoblastoma
What was the Knudson “2 hit” hypothesis?
Noticed there was patients with family history of retinoblastoma (familial form) & those without (sporadic)
Describe the Familial form of retinoblastoma?
Present earlier in childhood & often had bilateral multi-focal disease
Describe the Sporadic form of retinoblastoma?
Without family history presented later & only had
a single eye involved
What is a tumour suppressor gene (TSG)?
Anti-oncogene
What 3 things do you focus on when examining the optic nerve during ophthalmoscope?
- Margin
- Colour
- Cup
What does a big cup to optic disc ratio mean?
Potential Glaucoma
What are the 4 different types of abnormal optic discs?
- Swollen
- New vessels (diabetes)
- Cupped (glaucoma)
- Pale (optic atrophy)
Describe the 3 different causes of a swollen optic disc?
- Pseudo swelling- small disc, drusen (white accumulations)
- Genuine swelling
- Raised ICP- space occupying lesion, idiopathic intracranial hypertension, hydrocephalus
What is Retinopathy of Prematurity (ROP)?
Blinding neovascular retinal condition driven by hormones including vascular endothelial growth factor (VEGF)
What is a binocular indirect ophthalmoscope?
Wide field manual retinal examination for diabetes & retinopathy of prematurity
What is an Arclight?
Direct ophthalmoscope, Otoscope & Loupe
What are the 6 extra-ocular muscles & their innervation?
- Medial (CN III) & Lateral (CN VI) recti
- Superior & inferior recti (CN III)
- Superior (CN IV) & inferior (CN III) obliques
Describe the clinical presentations of a 3rd (oculomotor) cranial nerve palsy?
- Oblique diplopia
- Eye is ‘down & out’
- Diplopia every where
- Pupil dilated & ptosis
- Can be associated with aneurysm: needs urgent brain imaging & angiogram
Describe the clinical presentations of a 4th (trochlear) cranial nerve palsy?
- Oblique diplopia
- Head tilt
- Worse away from side of the
palsy if unilateral - Common after
head injury - Bilateral: might be congenital
Describe the clinical presentations of a 6th (abducens) cranial nerve palsy?
- Horizontal diplopia
- Worse far distance
- Worse towards side of the palsy if unilateral
- Bilateral: raised intracranial pressure might be present
Describe Age related Macular Degeneration (AMD)?
- Most common cause of blindness >65 years in high- income countries
- Types: wet & dry
What are the symptoms of age related macular degeneration (AMD)?
- Progressive reduction in
visual acuity - Metamorphopsia may suggest wet type
What are the potential treatments for wet & dry Age related macular degeneration (AMD)?
- DRY: rehabilitation
- WET: anti-VEGF injections
When/Where is diabetic retinopathy most common?
Main cause of blindness in working age ‘western’ countries
How does diabetic retinopathy cause blindness?
- Growth of new vessels, vitreous haemorrhage, tractional retinal detachment & rubeotic glaucoma
- Leakage of fluid from damaged vessels, Macular oedema with loss of central visual acuity
Describe the pathological steps of diabetic eye disease?
Chronic hyperglycaemia –> Glycosylation of protein/BM –> Loss of pericytes –> Reduced O2 transport –> VEGF produced –> Neo-vascularisation & leakage
What causes retinal detachment in diabetic retinopathy?
Scaring leading to traction between vitreous & retina
What leads to robotic glaucoma?
New vessel growth on iris
What are the 3 classifications of diabetic retinopathy?
- No retinopathy (screen)
- Non-proliferative retinopathy: Mild, Moderate, Severe (screen mild & refer mod-severe)
- Proliferative retinopathy (treat)
List the signs of non-proliferative diabetic retinopathy?
- Microaneurysms
- Dot & blot haemorrhages
- Hard exudates
- Cotton wool spots
- Abnormalities of venous calibre
- Intra-retinal microvascular abnormalities (IRMA)
What are the 4 classifications of Maculopathy?
- No maculopathy (screen)
- Observable (screen)
- Referable (refer)
- Clinically significant (treat)
What are the 6 potential treatments for Maculopathy?
- Stop smoking, weight, exercise
- Glycaemic control
- Blood pressure control
- Dyslipidaemia control
- Support renal function- ACE inhibitors
- Laser, anti-VEGF injections & surgery
Where do 80% of people with diabetes live?
In low & middle income countries
What is the main cause of blindness in “Western” countries?
Age related macular degeneration (AMD)
What is the main cause of blindness in “low income” countries?
Cataract
What are the 5 most common types of Dementia?
- Alzheimer’s
- Vascular
- Mixed
- Fronto-temporal
- Dementia with Lewy bodies
What is Dementia according to NICE guidelines 42?
Dementia is a generic term for clinical syndrome & progressive
How does Dementia affect the person (5)?
- Day to day memory
- Mood
- Language/
communication problems - Visuospatial skills
- Orientation
- Concentrating, planning, organising
List the signs & symptoms of Early “mild” stage Alzheimer’s?
- Forgetful
- Lose interest
- Mislaying items
- Poor judgement, hard to make plans/decisions
- Confusion
- Slower cognitive capacity
- Judging distance
List the signs & symptoms of Middle “moderate” stage Alzheimer’s?
- Fail to recognise people
- Time/place/events/getting lost
- Need help with personal care
- Difficulty in daily activities
- Safety
- Behavioural changes
List the signs & symptoms of Late stage Alzheimer’s?
- Unaware of time/place
- Confusion/comprehension
- Not recognise familiar faces
- Need assistance in eating
- Increased need in self case
- Incontinence
- Mobility problems
What is the role of the Caregiver in early stage Dementia?
- Emotional support
- Prompt & remind person about events, tasks to maintain involvement & independence
- Assistance with instrumental activities (personal finances, shopping)
What is the role of the Caregiver in middle stage Dementia?
- Communication strategies
- Help with personal care
- Help with activities of daily living (food preparation, dressing appropriately)
- Respond & manage behavioural disturbance & inappropriate behaviour
What is the role of the Caregiver in late stage Dementia?
- Care, support & supervision 24/7
- Assistance with eating & drinking
- Full physical care (bathing, toileting,
dressing, mobilizing) - Manage behavioural problems
What are the consequences of caregiving?
- Depression/anxiety
- Lower quality of life/wellbeing
- Worse health outcomes
- Sleep problems
- Socially isolated
- Role strain
- Family conflict
- Financial strain
- Sense of loss/grief
- Guilt/ resentment/ anger
What are 2 false beliefs of Dementia?
- Normal part of ageing
2. Nothing can be done
What are 4 sources of support for people with Dementia?
- Social services department of local authority/council
- Community psychiatric nurse
- Physiotherapy (mobility)
- Occupational therapy
How does Occupational therapy help with Dementia?
- Reminiscing & making life story book
- Recommending suitable exercise/
changes around home - Improve home safety
- Info accessing other support
- Advising carers